Virtual environment technologies are widely used in different applications, including engineering design, training, architecture, and entertainment. In order to improve realism and immersion, it is important to augment visual perceptions with matching sound stimuli and auralize the sound fields. The resulting auditory information can significantly help the user evaluate the environment in terms of spaciousness and sound localization.
Currently, interactive sound propagation and rendering in large-scale virtual environments composed of multiple moving sources and objects can present many problems and difficulties with respect to generating an accurate representation. These include large urban environments spanning kilometers and made up of tens or hundreds of buildings with multiple moving vehicles. Other scenarios include large indoor environments such as auditoriums, offices, or factories with volumes up to tens or hundreds of thousands of cubic meters. The model complexity and large dimensions of these spaces result in many acoustic effects including reflections, scattering between the objects, high-order diffraction, late reverberation, echoes, etc.
The most accurate propagation algorithms for modeling various acoustic effects are based on numerically solving the acoustic wave equation. However, the complexity of these methods increases as a linear function of the surface area of the primitives or the volume of the acoustic space, and as at least a cubic function of the maximum simulated frequency. Recently, many wave-based precomputation techniques have been proposed for interactive applications [16, 38, 27, 23, 42]. However, current algorithms are limited to static scenes and the computational and memory requirements increase significantly for large virtual environments.
Some of the widely used techniques for interactive sound propagation are based on geometric acoustics (GA) and use computations based on ray theory. These are used to compute early reflections and diffractions in static scenes [12, 36, 4] or to precompute reverberation effects [39, 4]. A major challenge is to extend these techniques to complex virtual worlds with multiple moving objects or sources. In a large environment, surface scattering and edge diffraction components tend to overshadow specular reflections after a few orders of reflection [20]. Recent advances in ray tracing are used to develop fast sound propagation algorithms for dynamic scenes [21, 26, 34], but these methods still cannot compute compute high-order edge diffraction or diffuse reflections at interactive rates.
Accordingly, there exists a need for systems, methods, and computer readable media for modeling interactive diffuse reflections and higher-order diffraction in virtual environment scenes.